The present invention relates generally to combustion-powered fastener-driving tools, and more particularly to new and improved valve mechanisms operatively integrated within dual combustion chamber systems incorporated within combustion-powered fastener driving tools in order to facilitate and enhance the operational efficiency attendant the introduction and mixing of air-fuel mixtures into and within the dual combustion chambers, as well as to similarly facilitate and enhance the operational efficiency attendant the scavenging and discharge of the combustion products out from the dual combustion chambers.
Dual combustion chamber systems have been heretofore incorporated within fastener driving tools, and as a result of the employment of such dual combustion chamber systems within fastener-driving tools, enhanced energy or power output levels have been able to be achieved for optimizing operational characteristics or parameters of the fastener-driving tools in connection with the driving of fasteners into underlying substrates. The dual combustion chamber systems generally comprise separate first and second combustion chambers, wherein a one-way check valve is effectively interposed between the first and second combustion chambers such that fluid flow only occurs in the direction extending out from the first combustion chamber and into the second combustion chamber. In addition, the first combustion chamber usually comprises a substantially elongated tubular structure, while the second combustion chamber usually comprises a substantially shorter, more compact structure. The overall structural arrangement of such dual combustion chamber systems can in fact be rendered compact by forming or fabricating the first combustion chamber in such a manner that the first combustion chamber has a substantially spiral or spool-type structure or configuration, and wherein further, the first combustion chamber effectively surrounds the second combustion chamber. Examples of such dual combustion chamber systems, as incorporated within combustion-powered fastener-driving tools, are disclosed within U.S. patent application Ser. No. 10/050,416 entitled COMBUSTION CHAMBER SYSTEM, which was filed on Jan. 16, 2002 in the name of Joseph S. Adams, and U.S. patent application Ser. No. 10/050,836 entitled COMBUSTION CHAMBER SYSTEM WITH SPOOL-TYPE PRE-COMBUSTION CHAMBER, which was also filed on Jan. 16, 2002 in the name of Joseph S. Adams.
A practical or operational concern in connection with the efficient cyclical operation or functioning of such fastener-driving tools having the aforenoted dual combustion chamber system incorporated therein is the introduction and mixing of the air-fuel mixtures into and within the combustion chambers, as well as the scavenging or discharge of the combustion products out from the combustion chambers. Conventionally, considerable time has in fact been required in order to adequately or properly achieve and complete the aforenoted air-fuel mixture introduction and mixing stages of the fastener-driving operational cycle performed by means of the combustion-powered fastener-driving tool, as well as the achievement and completion of the aforenoted scavenging or discharging stage of the fastener-driving operational cycle performed by means of the combustion-powered fastener-driving tool.
A need therefore exists in the art for a new and improved dual combustion chamber system for incorporation within combustion-powered fastener-driving tools wherein the efficiency of the introduction and mixing of the air-fuel mixtures into and within the combustion chambers, as well as the scavenging or discharge of the combustion products out from the combustion chambers, can be optimized.
Accordingly, it is an object of the present invention to provide a new and improved dual combustion chamber system of a combustion-powered fastener-driving tool, and new and improved valve mechanisms for incorporation within the dual combustion chamber system of the combustion-powered fastener-driving tool.
Another object of the present invention is to provide a new and improved dual combustion chamber system of a combustion-powered fastener-driving tool, and new and improved valve mechanisms for incorporation within the dual combustion chamber system of the combustion-powered fastener-driving tool, which effectively overcomes the various operational drawbacks and disadvantages characteristic of conventional or PRIOR ART dual combustion chamber systems.
An additional object of the present invention is to provide a new and improved dual combustion chamber system of a combustion-powered fastener-driving tool, and new and improved valve mechanisms for incorporation within the dual combustion chamber system of the combustion-powered fastener-driving tool, wherein the efficiency of the introduction and mixing of the air-fuel mixtures into and within the combustion chambers, as well as the scavenging or discharge of the combustion products out from the combustion chambers, can be optimized.
A further object of the present invention is to provide a new and improved dual combustion chamber system of a combustion-powered fastener-driving tool, and new and improved valve mechanisms for incorporation within the dual combustion chamber system of the combustion-powered fastener-driving tool, wherein the efficiency of the introduction and mixing of the air-fuel mixtures into and within the combustion chambers, as well as the scavenging or discharge of the combustion products out from the combustion chambers, can be optimized, and wherein further, the valve mechanisms may comprise various operational structures, such as, for example, a rotary valve mechanism, a rotary and linear valve mechanism, or a linear valve mechanism.
A last object of the present invention is to provide a new and improved dual combustion chamber system of a combustion-powered fastener-driving tool, and new and improved valve mechanisms for incorporation within the dual combustion chamber system of the combustion-powered fastener-driving tool, wherein the efficiency of the introduction and mixing of the air-fuel mixtures into and within the combustion chambers, as well as the scavenging or discharge of the combustion products out from the combustion chambers, can be optimized by means of a single valve mechanism which can operatively control the ingress of atmospheric air into the combustion chambers, the egress of combustion products out from the combustion chambers, and the fluid flows between the first and second combustion chambers attendant the VENTING, MIXING, and FIRING stages of an overall combustion cycle.
The foregoing and other objectives are achieved in accordance with the teachings and principles of the present invention through the provision of a new and improved dual combustion chamber system of a combustion-powered fastener-driving tool, and new and improved valve mechanisms for incorporation within the dual combustion chamber system of the combustion-powered fastener-driving tool, wherein, in accordance with a first embodiment of the present invention comprising a rotary valve mechanism, there is provided a valve mechanism which is rotatably movable between three separate and distinct positions so as to fluidically inter-connect the first and second combustion chambers of the dual combustion chamber system, during three different stages of an overall combustion cycle, by passageways other than the passageway or conduit which conventionally connects the first and second combustion chambers and which is controlled either by means of the aforenoted check valve structure or by means of a suitable port or connecting orifice. More particularly, when the rotary valve mechanism is rotated to its first position, corresponding to the first VENTING stage of the combustion cycle, and disposed at such position for a predetermined period of time as a result of the completion of a previous FIRING stage of the combustion cycle and the removal of the tool from its engaged position with the underlying substrate or workpiece, atmospheric air is introduced into the first combustion chamber, the air and combustion products, which are present within the first combustion chamber from a previous FIRING stage, are transmitted from the first combustion chamber into the second combustion chamber, and the air and combustion products, which are present within the second combustion chamber from the previous FIRING stage, are exhausted from the second combustion chamber to atmosphere.
When the rotary valve mechanism is subsequently rotated to its second position, corresponding to the second MIXING stage of the combustion cycle, and disposed at such position for a predetermined period of time as a result of the tool being disposed in contact with the underlying substrate or workpiece and prior to the initiation of the FIRING stage of the combustion cycle by means of the tool trigger mechanism, atmospheric air is no longer introduced into the first combustion chamber, and combustion products are no longer exhausted from the combustion chambers to atmosphere. To the contrary, fuel is introduced into the first combustion chamber, and the resulting air-fuel mixture is continuously circulated from the first combustion chamber into the second combustion chamber, and from the second combustion chamber back into the first combustion chamber, so as to achieve good MIXING of the air-fuel mixture. After the MIXING stage of the combustion cycle has been completed for a period of time until the FIRING stage of the combustion cycle is initiated by means of the tool operator actuating the tool trigger mechanism, the rotary valve mechanism is rotated to its third FIRING position as a result of the actuation of the tool trigger mechanism, and is disposed at such position for a period of time during which the FIRING stage of the combustion cycle is achieved and until the tool is released from its engaged position with the underlying workpiece or substrate.
During the FIRING stage of the combustion cycle, the air-fuel mixture is ignited within the first combustion chamber, and it is noted that the first combustion chamber is only fluidically connected to the second combustion chamber through means of the fluid passageway controlled by either the aforenoted check valve or the port or connecting orifice. Accordingly, the flame front travels through the first combustion chamber, the flame front then passes into the second combustion chamber thereby igniting the combustible air-fuel mixture present within the second combustion chamber, and the energy or power generated within the second combustion chamber is directed against a suitable piston-driver assembly which operatively drives a fastener out from the combustion-powered tool and into the substrate or workpiece. After the tool has been fired and the fastener has been driven into the workpiece or substrate, the trigger mechanism is deactuated and the tool is removed from its engaged position with the substrate or workpiece so as to permit the rotary valve mechanism to again be rotated to its first VENTING position whereby fresh air can again be introduced into the combustion chambers such that combustion products can again be exhausted, purged, or scavenged from the combustion chambers in preparation for a new or subsequent combustion cycle.
In accordance with a second embodiment of the present invention which comprises a combination linearly and rotary movable valve mechanism, the valve mechanism likewise includes suitable structural components which cooperate together so as to be capable of similarly performing the various operational steps, characteristic of the aforenoted VENTING, MIXING, and FIRING stages of the combustion cycle, as were able to be performed by means of the aforenoted rotary valve mechanism. More particularly, a first valve housing or component, having the first serpentine combustion chamber defined therein, annularly surrounds a second valve housing or component which defines the second combustion chamber therein. The first valve housing or component is linearly movable with respect to the second valve housing or component, and is also rotatable with respect to the second valve housing or component. Accordingly, when the first and second valve housings or components are disposed at first positions with respect to each other, fresh air is admitted into the second combustion chamber, the fresh air is then conducted into and through the first combustion chamber, and the fresh air is then exhausted into the atmosphere whereby combustion products, present within the first and second combustion chambers from a previous FIRING stage of the overall combustion cycle, are VENTED, PURGED, or SCAVENGED.
Subsequently, when the first valve housing or component is linearly moved with respect to the second valve housing or component as a result of the combustion-powered tool being forced into contact with the workpiece or substrate into which a fastener is to be driven, the fresh air intake and exhaust ports are closed, fuel is injected into the first combustion chamber, and the air-fuel mixture is recirculated through the first and second combustion chambers so as to achieve the MIXING stage of the over-all combustion cycle until the operator initiates ignition. Subsequently, upon completion of the MIXING stage of the combustion cycle, when the FIRING stage of the combustion cycle is to be initiated, the first valve housing or component is rotated with respect to the second valve housing or component, as a result of being operatively connected to the tool trigger mechanism, whereupon the air-fuel mixture being ignited within the first combustion chamber, the flame front traverses the first combustion chamber, enters the second combustion chamber through means of the one-way check valve, port, or orifice separating the first combustion chamber from the second combustion chamber, and ignites the air-fuel mixture present within the second combustion chamber so as to in fact initiate the FIRING stage of the combustion cycle. Accordingly, the energy and power generated by means of such combustion within the second combustion chamber acts upon a suitable piston-driver assembly of the fastener-driving tool for driving a fastener out from the combustion-powered fastener-driving tool.
In accordance with a third embodiment of the present invention which comprises a linearly movable valve mechanism, the valve mechanism likewise includes suitable structural components which cooperate together so as to be capable of similarly performing the various operational steps, characteristic of the aforenoted VENTING, MIXING, and FIRING stages of the combustion cycle, as were able to be performed by means of the aforenoted rotary and combination linear-rotary valve mechanisms. More particularly, the linearly movable valve housing or component, having the first serpentine combustion chamber defined therein, annularly surrounds the second combustion chamber therein. The first and second combustion chambers have fluid passageways defined therein which are adapted to be fluidically aligned with respect to each other or non-aligned with respect to each other in order to achieve the various VENTING, MIXING, and FIRING stages of the combustion cycle. More particularly, when the outer valve housing is disposed at a first position, the fluid passageways of the first and second combustion chambers are aligned with respect to each other, and intake air and exhaust air are permitted to enter into the combustion chambers and exit out from the combustion chambers so as to achieve the VENTING of the first and second combustion chambers. When the outer valve housing is linearly moved to a second position as a result of the tool being disposed in contact with the underlying workpiece or substrate, the intake and exhaust ports are closed, however, the first and second combustion chambers are still fluidically connected to each other through means of the fluid passageways so as to achieve MIXING of the air-fuel mixture within the first and second combustion chambers. When the outer valve housing is linearly moved still further to its third position as a result of the actuation of the tool trigger mechanism, the fluidic passageways between the first and second combustion chambers are closed or no longer aligned with each other whereby combustion, initiated within the first combustion chamber, can only be conveyed into the second combustion chamber through means of the one-way check valve, or the port or orifice, so as to achieve the desired FIRING stage of the combustion cycle. Return of the outer housing to its first position, as a result of the deactuation of the tool trigger mechanism and the disengagement of the tool with respect to the substrate or workpiece, facilitates a new VENTING cycle.